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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>, paulus@samba.org,
 mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
 LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V2 00/10] KASan ppc64 support
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Date: Wed, 26 Aug 2015 22:44:35 +0530
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Andrey Ryabinin <ryabinin.a.a@gmail.com> writes:

> 2015-08-26 11:26 GMT+03:00 Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>:
>> Hi,
>>
>> This patchset implements kernel address sanitizer for ppc64.
>> Since ppc64 virtual address range is divided into different regions,
>> we can't have one contigous area for the kasan shadow range. Hence
>> we don't support the INLINE kasan instrumentation. With Outline
>> instrumentation, we override the shadow_to_mem and mem_to_shadow
>> callbacks, so that we map only the kernel linear range (ie,
>> region with ID 0xc). For region with ID 0xd and 0xf (vmalloc
>> and vmemmap ) we return the address of the zero page. This
>> works because kasan doesn't track both vmemmap and vmalloc address.
>>
>> Known issues:
>> * Kasan is not yet enabled for arch/powerpc/kvm
>> * kexec hang
>> * outline stack and global support
>>
>
> Is there any problem with globals or you just didn't try it yet?
> I think it should just work. You need only to add  --param
> asan-globals=0 to KBUILD_CFLAGS_MODULE
> to disable it for modules.

I am hitting BUG_ON in early vmalloc code. I still haven't got time to
debug it further. Should get to that soon.

-aneesh